<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="allChecked"/>
    </label>
    <span> <span>已完成{{checkedNum}}</span> / 全部{{ todos.length }} </span>
    <button class="btn btn-danger" @click="Alldelete">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
  props: ["todos","checkAll","Alldelete"],
  computed: {
    allChecked: {
      set(value) {
        this.checkAll(value)
      },
      get() {
       return(
        this.todos.every((item) => item.done) && this.todos.length !== 0
       )
      },
    },
    checkedNum(){
      return this.todos.reduce((p, c) => (c.done ? p + 1 : p), 0);
    }
  },
};
</script>

<style>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>
